# Re: 2017-03-06- UTC, TImeZone, DayLight Saving Shifts, Enconding

```On 19.03.2017 14:59, Joe Touch wrote:
>>>> and now look at e.g. the calendar of Microsoft Outlook and look for
>>>> the beginning and ending of a celebration day ...
>>> The begin and end of a workday are configurable parameters within
>>> Outlook. All-day events start at the beginning of a day (12am for
>>> 12-hour clocks, 00:00 for 24-hour). This is what should be expected.
>> I  was not talking about a workday ..., I was talking about the general problem
>> the last day of the year ends at 11:59 pm and not 12:00 am - as this is the time the next day starts;
> Why is that a problem?
because the software behaviour is this invalid ...

>   Would it help to think of 12 being 0?
>
> Then we'd have 0:00am (same as 00:00 in a 24-hour system) and 00:00pm (12:00 in a 24-hour system).
>
> Except we couldn't make clock faces using Roman numerals, because they lack a zero. And it wouldn't match the system in current use.
>
>> by the way 12:00 pm is not defined,
> Then when did I have lunch yesterday?
Sorry, the AM/PM system doesn't know of a zero hour ...
> Every day starts at 1200am, hits 1200pm at the start of the second half, and ends at 11:59:59.9999999....
>
> Except in leap years when it ends at 11:59:60.9999999...
wrong, leap years have a February 29th ...
>
>> as the day has only 24 hours = 1440 minutes = 86400 seconds
> That depends on how you define seconds
wrong, there is only one definition for second, and that is

in German:  "Die Sekunde ist das 9 192 631 770fache der Periodendauer
der dem Übergang zwischen den beiden Hyperfeinstrukturniveaus des
Grundzustandes von Atomen des Nuklids Cäsium-133 entsprechenden Strahlung;"
in English: "Thesecondis9192631770 timestheperiodsof
theground stateofatomsof thenuclideof Cs-133;"
> and whether a leap second is involved, but generally, yes.
> When you count 0..59 there are 60 items for both minutes and seconds. Counting 12,1,2...9,10,11 yields 12.
>
> You haven't shown a problem yet.
not as image, I showed in words ... "the calendar of Microsoft Outlook
and look for the beginning and ending of a celebration day ..."

look at this image:
https://cdn.pbrd.co/images/LkqU6dJCk.png
there you see the end of the "appointment" is the beginning of the next
day which is invalid ...

as I said: "nearly no software does it correct ..."
```

Received on Sunday, 19 March 2017 14:55:47 UTC